When you are photographing sports you should try to get some good action shots, but you should also remember the thrill of victory and the agony of defeat. Some of the greatest sports photos ever taken are non-action shots. If you know the sport you are photographing well it will help, if not, you may want to do some research. If you are waiting for somebody to hit a home run during a football game, well, good luck.
Knowing when to take the shot in sports is just as important as the equipment. If you want action shots, set your camera up in a good spot where you know there will be plenty of it. If you do get a good spot and you can use a tripod, go for it since it will cut down on camera shake and vibration. If you can't get close enough you should use a zoom lens to compensate. Make sure you have the scene in focus and experiment with action-freezing shots and slower shutter photos that will give a blurred background, which shows you the speed of your subject.
Make sure you have adequate equipment and lighting. Long, fast lenses are good for sports and you should use high speed film in darker conditions. Fast shutter speeds will help you freeze the action and panning can show you speed. Continuous shooting modes may also help you get quality action photos.